Various aspects of the formation of gap junctions will be studied using Novikoff hepatoma cells taken from suspension culture. Freeze-fracture techniques will be used to quantitate the changes in numbers and distribution of presumptive junctional particles during the earliest stages of formation. Electrophysiological and dye-passing techniques will be used to determine the effects of temperature, pH, CO2, serum on degree and extent of junctional formation. Correlated freeze-fracture and electrophysiological studies will be made of junctional formation between daughter cells following mitosis.